Occurrence of Phytophthora citrophthora on Syringa vulgaris in Poland

Leszek B. Orlikowski, Grażyna Szkuta


Phytophora citrophora was isolated from dieback shoots, base of diseascd stems and top parts of lilac plants during 3 vegetation periods. The species was detected from about 75% of analysed plant parts. On V8 juice agar and potato-dextrose agar the quickest growth of the species was observed at 25·30°C but development did not occur at 5° and 35°C. Zoosporangia were mostly papillate from spherica1 to ellipsoidal with average dimensions 45.6 x 31.5 μm. P. citrophthora from 5 host plants caused necrosis development of leaves and stem pars of lilac but the quickest spread of disease occurred when plants or their parts were inoculated with isolates from Syringa vulgaris and Pieris japonica. It indicates that the pathogen may be transmissed in nurseries from diseased pieris grown near lilac.


lilac; dieback; blight; Phytophthora; colonisation; host plants

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